Exhaust gas coolers are used today in order to be able to reduce the emission of nitrous oxides and particulates significantly. Part of the exhaust gas is diverted in the exhaust gas manifold and then conducted through the exhaust gas cooler where it is cooled. The cooled exhaust gas is then mixed with the aspirated fresh air and supplied as a mixture to the internal combustion engine again for combustion. Because of the comparatively high exhaust gas temperatures, such an exhaust gas cooler is exposed to high thermal load, wherein the cooler in all cases must be dimensioned and configured such that it is not damaged because of the comparatively high exhaust gas temperatures.
Exhaust gas coolers are in principle either bolted directly to the internal combustion engine via brackets, or mounted on fixed brackets and then attached with clamping straps. The exhaust gas cooler here has a housing in which pipes are installed which carry the exhaust gas and about which coolant can flow. Exhaust gas coolers which are integrated in a cavity of the housing of the internal combustion engine, for example an engine block or a crankcase, and hence can be connected directly to the cooling system of the internal combustion engine, constitute a significant simplification.
EP 1 099 847 A2 describes a generic internal combustion engine with a housing and cavities arranged therein through which a coolant can flow for cooling the internal combustion engine. The internal combustion engine here also has an exhaust gas cooler for cooling exhaust gas to be supplied to a combustion process. As well as the exhaust gas cooler, in addition an oil cooler is also integrated in the cooling circuit of the internal combustion engine, wherein the exhaust gas cooler is further away from the main coolant flow than the oil cooler, which carries the risk that insufficient coolant will flow through the exhaust gas cooler. Rather, the exhaust gas cooler protrudes slightly and here forms a dead space. Thus the thermal sustainability may be limited.
DE 10 2004 015 487 A1 discloses an internal combustion engine with a crankcase and a cylinder head, to which an exhaust manifold and a fresh gas pipe are attached. These two pipes are connected to an exhaust gas cooler via an exhaust gas recirculation line, with an exhaust gas recirculation valve connected in the exhaust gas recirculation line. In order to be able to improve the mounting of the exhaust gas recirculation device on the internal combustion engine, the housing of the exhaust gas cooler is an integral part of the crankcase in at least one part region.
EP 2 036 097 A1 discloses a further generic internal combustion engine, as does WO 2007/003303 A1.
The disadvantage with the exhaust gas coolers known today is that these are comparatively costly and are constructed from many individual components, even for low performance requirements for the exhaust gas cooler itself. The high costs are due in particular to the comparatively costly housing which is up to 2 mm thick.